Hydrocarbon production and refining includes many high temperature and high pressure pipeline fluids that are conveyed in assorted conduits. The direction and flow of these fluids is at least partially controlled by valves and valve assemblies. These assemblies require periodic maintenance or replacement of certain components during operation of a conduit. Maintenance and replacement inherently includes a risk of personnel exposure to pipeline fluids. Valves having a stem, such as slab valves and expanding valves, may leak, spray, or otherwise expose service personnel to the pipeline fluids. Additionally, material suspended in pipeline fluids or the fluids themselves may interfere with the operation of a valve and the maintenance thereof.